1. Field of the Invention
The present invention relates to a tape drive control apparatus for use with a data recorder, tape recorder and so on, and is directed more particularly to a tape drive control apparatus for use with a tape recorder and so on in which a pinch roller is not used by which a tape is moved apart from the capstan upon the high speed tape transportation mode and stop mode of the tape.
2. Description of the Prior Art
In a prior art tape drive control apparatus for use with a tape recorder shown in FIG. 1, a tape 2 wound on a supply reel 1 passes through a guide post 3, a guide roller 4 and so on, then contacts with a magnetic head group 5, is wound on a capstan 6 with an angle .theta. (which is generally greater than 90.degree.), passes a guide post 7, and then is taken up by a take-up reel 8. In some examples, both the guide posts 3 and 7 are mounted on a tension servo arm (not shown) so as to keep the tension of the tape 2 constant.
Upon the recording or reproducing mode, the tape 2 is wound sufficiently on the capstan 6 which is rotated at constant speed by a capstan motor (not shown). Thus, the tape 2 is transported at a constant speed, without slipping by the friction force which is determined by the urging force defined by the winding angle .theta. of the tape 2 on the capstan 6 and the tape tension and the frictional factor on the contacting surface of the tape 2 with the capstan. Accordingly, with the prior art apparatus shown in FIG. 1, no abrasion is caused on the tape 2 and no abnormal tension is caused in the tape 2. This is different from the case where a pinch roller is used to urge the tape against the capstan.
However, with the prior art apparatus shown in FIG. 1, when its operation mode is changed to the fast forward mode or stop mode, the rotational speed of the capstan 6 is varied. Therefore, if the inertial mass of the capstan system as selected is large, the acceleration characteristics thereof deteriorates and the time interval, within which the capstan 6 arrives at a normal rotational speed, becomes long. On the contrary, if the inertial mass of the capstan system as selected is small, its mechanical impedance becomes small and hence the capstan system is reduced in stability and is responsive fluctuation caused by external loads with the result that the value of wow and flutter deteriorates. Therefore, the prior art apparatus can not be used, as it is, in a tape recorder for audio use which requires severe acceleration characteristics or wow and flutter value.